Lawson said at a press conference in Lansing, Mich., that he had been a railroad engineer before quitting a couple of weeks ago after he had discovered he had won. Lawson, who said he has two daughters, was joined at the announcement by his mother, sister and brother-in-law.

The winning ticket for the Aug. 15 jackpot -- the third largest ever for Powerball -- was purchased at a Sunoco gas station and convenience store in the town of Lapeer, about 50 miles north of Detroit. Lawson said he grew up in Fort Smith, Ark., and moved to Lapeer about 10 years ago.

Lawson described the moment he learned his life was about to change when he checked the ticket.

Lawson took the option to receive the money in lump sum -- which would be about $224 million before taxes. Powerball officials say most winners opt for the one-time payout.

Al Goldis / AP

Donald Lawson, right, a 44-year-old Lapeer, Mich. resident, laughs with his mother at a news conference in which he claimed the $337 million Powerball prize on Friday at the Michigan Lottery headquarters in Lansing, Mich.

A Powerball ticket costs $2.

In March, three winning tickets shared the largest U.S. lottery jackpot, the $656 million Mega Millions drawing.

The last big Powerball jackpot was won in February by Louis White of Rhode Island. That prize was worth $336 million and at the time was the third largest Powerball jackpot in history. The prize won by Lawson edged that one for the No. 3 spot.

So what are his immediate plans?

"I'm going to escape for now, and go somewhere safe," he said.

And will all that money change him?

"I'm a millionaire now, but I like McDonalds," he said. "I don't like mignons or lobster ... I want a simple life and that's what I'll continue to do."

Residents in the tiny town of Lapeer, Mich., are consumed with speculation as to which of their neighbors holds the winning Powerball lottery ticket with a valued jackpot of $337 million.